Fluid oscillator system



United States Patent 3,517,686 FLUID OSCILLATOR SYSTEM Brooks Lyman,Pound Ridge, N.Y., and Robert F. OKeefe, Trumbull, Conn., assignors toPitney-Bowes, Inc., Stamford, Conn., a corporation of Delaware FiledJuly 13, 1966, Ser. No. 564,821 Int. Cl. F15c 1/08 U.S. Cl. 137-815 6Claims ABSTRACT OF THE DISCLOSURE A fluidic oscillator that includes asingle turbulence type fluid amplifier, to the collector of which isconnected a plenum chamber and to the side of the interaction chamber ofwhich is connected a fluid outlet line whereby the alternate automaticfilling and emptying of the plenum chamber produces correspondingperiodic fluid pressure changes in the said outlet line.

This invention relates to a novel pure fluid oscillator system. Moreparticularly the invention relates to a novel fluid oscillator systemwherein a single turbulence type pure fluid amplifier is used to afforda varying fluid pressure source.

Fluid oscillators have been made using wall attachment type fluidamplifiers equipped with a feed back coupling from the amplifier outputline to a control line thereof. While this type of arrangement may bepractical for certain relatively high frequency applications it has notbeen found satisfactory in many cases where relative low fluidoscillator frequencies are desired, i.e. frequencies less than say 150cycles per second.

The primary object of the instant invention is to provide a simple,practical, low cost pure fluid oscillator system which may be arrangedto afford most any desired operational frequency of less than 150 cyclesper second.

Another object of the invention is to provide a relatively low frequencyfluid oscillator system wherein a turbulence amplifier is arranged toautomatically control alternate fluid flows through two separate flowlines.

Another object of the invention is to provide an improved fluidoscillator system having a control means for interrupting the fluidoutput pulse sequence as desired.

Other objects of the invention will become apparent as the disclosureprogresses.

In the drawings:

FIG. 1 is a plan view and shows the configuration for the turbulenceamplifier used in the instant fluid oscillator system.

FIG. 2 is a plan view in partial section of the instant oscillatorsystem and particularly illustrates the cover plate construction of theinstant device.

FIG. 3 is a lower end view of the apparatus shown in FIG. 2.

FIG. 4 is a cross sectional view taken along section line 44 of FIG. 2.

FIG. 5 is a diagrammatic sketch (enlarged four times from FIG. 1)illustrating the size and location of the vent holes in relation to theinteraction chamber of the instant turbulent amplifier.

FIG. 6 is a diagrammatic sketch illustrating the fluid pressure outputpulses generated by the present fluid oscillator system.

The instant fluid oscillator system comprises in essence a turbulentamplifier which is provided with a supplemental output line and which iscoupled to a means for cyclically increasing to a predetermined levelthe loading on the collector of the amplifier.

Referring to FIGS. 1-4 a laminated construction is illustrated for theturbulence amplifier unit 10. Unit 10 3,517,686 Patented June 30, 1970comprises a lower grooved plate 11 and an upper cover plate 12 which issealingly secured by any suitable means to said lower plate so as tothereby establish the flow passage network to be described below. Theconfigurations of the fluid flow passages are largely determined by thenature of the grooves, chambers, etc. that are formed in the upper faceof said lower plate 11 and particular reference to FIGS. 1 and 5 will bemade in connection with a detailed description of the shape and extentof such grooves and chambers. The instant turbulence amplifier includesan emitter which is essentially defined by an elongated straight groove13 which has an upstream end that communicates with a supply chamber 14and a downstream end that communicates with an interaction chamber 15.Chamber 15 is substantially symmetrically arranged with respect to thelongitudinal axis 16 of the emitter groove 13 and includes twolongitudinal side walls 17 and 18. The downstream end of interactionchamber 15 is formed with two concave end walls 20 and 21 whichterminate at projections 22 and 23 that extend slightly upstream in thechamber 15, as illustrated in FIG. 1, and define a collector orifice oropening 24 for the instant turbulence amplifier. The collector of theinstant unit 10 is essentially defined by an elongated straight groove25 which is coaxially disposed with respect to the emitter groove 13.The upstream end of the collector groove 25 communicates with saidinteraction chamber while the downstream end thereof communicates withan output chamber 26.

A laterally extending supplementary output line or groove 30 is alsoformed in the upper face of plate 11, one end thereof communicating witha downstream portion of the interaction chamber 15 through side wall 17,while the other end thereof communicates with an outlet chamber 31. Theaxis of groove 30 is disposed substantially normal to the axis 16 of theemitter groove 13. A laterally extending control line or groove 32 isformed in plate 11, one end theerof communicating with an upstreamportion of the interaction chamber through the opposite side wall 18 ofthe chamber 15, While the other end thereof communicates with a signalchamber 33. The axis of groove 32 is also disposed substantially normalto the axis 16 of the emitter groove 13.

The lower plate, which is grooved as above described, is sealinglycovered by the plate 12 as illustrated in FIGS. 2-4. The cover plate 12is formed with a plurality of suitable holes or bores which arerespectively adapted to receive a plurality of tubular fittings 40-45,the latter being respectively secured in said bores by any suitablemeans such as soldering, brazing, etc. as is illustrated at 46 of FIG.4. The tubular fittings 40, 41, 42, 43, 44, 45 are located in the coverplate at the positions shown in FIG. 2 and respectively communicate withthe various grooves and chambers in the amplifier at points denoted bythe dotted line circles 40a, 41a, 42a, 43a, 44a, 45a, respectively, ofFIG. 1. The tubular fitting 40 is adapted to be pneumatically coupled toa fluid pressure source and fittings 43 and 44, which are provided forventing purposes, operatively communicate with the respective sideportions of the downstream end of the interaction chamber 15. Only thelower portions 47, FIG. 5, of the symmetrically arranged vent holesformed in the cover 12, as represented by the said dotted line circles44a and 43a of FIG. 1 overlap the interaction chamber 15, theseoverlapping portions collectively representing the effective exhaust orventing area for the instant amplifier. These vent holes afford exhaustconduit means having a predetermined fluid flow impedance. The fitting41 may be connected to a means for generating a fluid input signal thatis capable of controlling the operation of the instant turbulenceamplifier, while fitting 42 is connected so as to supply oscillatingfluid pressure to a downstream device. The fitting 45 is connected to aclosed container 50, FIG. 3, having therein a plenum chamber 51' ofpredetermined volume, the chamber 51 acting as a predetermined impedanceor load with respect to the collector of the instant turbulenceamplifier.

The configuration of the groove and chamber arrangement formed in plate11 is shown to actual scale in FIG. 1; the width W of groove 13 having avalue of .015 inch. The actual diameter of holes 43a (see FIG. and 44ais .062. inch. All the above described grooves and chambers havesubstantially rectangular cross sectional shapes, the depth of grooves13, 24, 30, 32 and chamber 15 being approximately .015 inch and thewidth of the grooves 30 and 32 being .008 inch. It will be understoodthat various other ranges and combinations of dimensions may be usedhere.

The operation of the instant device will now be described. Fluid, e.g.air, from a suitable pressure source flows through fitting 40, chamber14, emitter groove 13 and into the interaction chamber 15. The elongatednature of the emitter 13 causes a laminar type air jet to issue from thedownstream end 19 of the emitter and to flow down'the length ofinteraction chamber 15 and into the upstream end 24 of the collectorgroove 25. This essentially laminar fluid flow will cause the pressurein the collector groove 25 and the plenum chamber 51 to increase until apredetermined pressure loading at the collector exists at which time thelaminar flow in the fluid jet received by the collector groove 25becomes turbulent with much of the fluid then exhausting through theventing fittings 43, 44. Under these turbulent flow conditions the fluidimpact pressure at the collector opening 24 begins to decrease and thefluid then under higher pressure in the plenum chamber 51 commences toflow back into chamber 15 through the collector groove 25. At this timethen fluid is being directed into chamber 15 from both the emitter andcollector ends thereof and a rapid increase in the pressure in thechamber 15 and output groove 30 occurs in that the amplifier ventingmeans is momentarily unable to conduct away the relatively large amountof fluid then being pumped into said chamber 15. The sudden pressureincrease in output line 30 initiates a fluid pressure output pulse orflow through the fitting 42. This output pulse is of short durationbecause the said reverse flow of fluid from the plenum chamber 51 to theinteraction chamber 15 soon effectively empties chamber 51 whereupononly the normal amount of fluid then enters chamber 15 by way of theemitter groove 13. This causes the output pulse or flow in fitting 42 toterminate thus restoring in chamber 15 those pressure conditions which-will permit the reestablishment of a laminar flow in the emitter jet.This in turn causes the pressure in collector groove 25 and chamber 51to again rise until it again reaches said predetermined pressure levelwhereupon another automatic pressure switching cycle commences. Theabove explanation of why the instant oscillator system produces theautomatic cyclic pressure switching action is somewhat conjectural.

The automatic cyclic switching of the amplifier operation back and forthbetween a laminar flow state, wherein fluid flows into the collectorgroove 25, and a turbulent flow state, wherein fluid flows out throughoutlet fitting 42 constitutes a reliable low speed fluid oscillatorsystem. It has been found that such a system has reasonably precisetiming characteristics for any given set of structural conditions andfluid supply pressure conditions. FIG. 6 illustrates the rather uniformperiod of time t between the successive pressure spikes 52 as measuredat the outlet fitting 42. The following table of operation for theinstant type of oscillator system was derived using a FIG. 1 typeturbulent amplifier having various sized chambers 51, the emitter groovewidth W being .015 inch and the air supply pressure being approximately1 p.s.i.

Volume of chamber 61, Period (t), Frequency, cycles cubic inchesmilliseconds per second The operational flucturations from the abovenoted time and frequency values did not vary more than approximately 3%.The maximum frequency obtained here was approximately cycles per second.

If it is desired to interrupt the operation of the instant oscillatorsystem a fluid pressure signal may be introduced into the signal fitting41 whereupon the automatic alternate mode switching of the turbulenceamplifier ceases and the amplifier remains in the said turbulentoperational mode for as long as said signal remains applied.

The instant type of relatively low frequenc fluid oscillator system hasbeen tested and found to be relatively accurate in producing apredetermined sequence of timed fluid pulses.

What is claimed is:

1. A fluid oscillator system comprising:

an emitter adapted to issue a laminar jet of fluid;

a collector operatively positioned with respect to said emitter so as tobe capable of receiving fluid flow from said emitter;

means defining an interaction chamber between said emitter andcollector;

means for venting said interaction chamber;

means defining a fluid plenum chamber, said plenum chamber communicatingwith said collector;

means defining an output line that communicates with said interactionchamber;

said laminar jet of fluid from said emitter initially causing saidplenum chamber to be filled so that the resultant operative loading atthe amplifier collector causes said laminar jet of fluid to becometurbulent, a reverse fluid flow then occurring from said plenum chamberto said interaction chamber which reverse flow causes a temporarypressure rise in said output line whereafter a laminar fluid flow isautomatically reestablished in said interaction chamber and said plenumchamber is again filled, the successive pressure increases in saidoutput line being in substantially uniform timed sequence; and

fluid conduit means defining a control line which communicates with saidinteraction chamber so that when a control signal is applied throughsaid control line said successive pressure increases in said output lineare interrupted.

2. A fluid oscillator system comprising:

a main body;

said main body having an elongated supply line formed therein, saidsupply line being adapted to be coupled to a source of fluid pressureand to issue a laminar jet of fluid from the downstream end thereof;

said main body having an interaction chamber formed therein, saidchamber communicating with the downstream end of said supply line;

said main body having a fluid receiving collector line formed therein,the upstream end of said collector line communicating with saidinteraction chamber and being arranged to receive fluid flowing fromsaid supply line across said interaction chamber;

said main body having at least one fluid venting line formed thereinthat communicates with said interaction chamber;

means defining a pressure loading chamber, said loading chambercommunicating with said collector line;

said main body having an output line formed therein which communicateswith said interaction chamber;

the flow of fluid from said supply line automatically alternatingbetween laminar flow that is directed into said collector line andturbulent flow at least part of which flows into said output line, theresultant intermittent fluid flow through said output line aflording anoscillating fluid pressure source;

said main body having a control line formed therein 'which communicateswith said interaction chamber and which is operable ,when a controlsignal is applied therethrough to control the fluid flow through saidinteraction chamber,

3. Apparatus as defined by claim 2 wherein said loading chamber issubstantially closed except for its connection with said interactionchamber.

4. A fluid oscillator system comprising:

a turbulence type fluid amplifier having an interaction chamber, anemitter and a collector, said emitter normally issuing a laminar jet offluid which is received by said collector;

means defining a predetermined fluid vent for said interaction chamber;

means for applying a predetermined pressure loading to the collector ofsaid turbulence amplifier; and

an output line communicating with said interaction chamber;

the flow of fluid through'said interaction chamber automaticallyalternating between a laminar flow that is directed into said collectorand a turbulent flow a portion of which flows into said output line, theresulant intermittent fluid flow through said output line affording anoscillating fluid pressure source.

5. Apparatus as defined by claim 4, additionally comprising: 1

control means for interrupting the intermittent flow of fluid throughsaid output line.

6. A fluid oscillator system that automatically switches between laminarand turbulent fluid flow conditions comprising a main body:

said main body having an elongated supply. line formed therein that isarranged to be coupled to a source of fluid pressure so as toetfectively define an emitter that is adapted to issue a laminar jet offluid from the downstream end thereof;

said main body having an interaction chamber formed therein, saidchamber communicating 'with the downstream end of said emitter;

said main body having a fluid receiving line formed therein thateflectively defines a collector, the upstream end of said collectorcommunicating with said interaction chamber and being arranged insubstantial axial alignment with said emitter so as to receive fluidflowing from said emitter across said interaction chamber;

said main body having at least one fluid venting line formed thereinthat communicates with said interaction chamber at a point adjacent thedownstream end of said interaction chamber; means for establishing apredetermined fluid flow impedance in said venting line;

means defining a pressure loading chamber, said loading chambercommunicating with said collector;

said main body having an output line formed therein which communicateswith said interaction chamber;

the said laminar jet issuing from said emitter initially flowing intosaid collector thereby filling said pressure loading chamber until at aparticular pressure level said laminar jet automatically becomesturbulent and a reverse fluid flow occurs through said collector wherebyfluid enters said interaction chamber from both said emitter and saidcollector so that the said impedance in said venting'line causes aportion of the fluid flow entering said interaction chamber to flow outthrough said output line in the form of-a pressure pulse of relativelyshort duration until the said pressure loading chamber is substantiallyemptied whereupon said laminar jet is automatically reestablished so asto start the next cycle of automatic switching back and forth betweensaid laminar and turbulent fluid flow conditions and thus automaticallygenerating successive fluid pressure pulses in said output line.

References Cited UNITED STATES PATENTS 1,628,723 5/1927 Hall 137-815 XR3,159,168 12/1964 Reader 137-81 .5 3,204,652 9/ 1965 Bauer 137--81;.53,228,410 1/ 1966 Warren et al. 137'81.5 3,258,023 6/1966 Bowles137--81.5 3,269,419 8/1966 Dexter 137-81.5 3,272,215 9/1966 Bjornsen etal. 13781.5 3,295,543 1/1967 Zalmanzon 137-815 3,362,421 1/ 1968Schaifer 137-815 3,275,015 9/1966'- Meier l3781.5

SAMUEL SCOTT, Primary Examiner

